diff --git a/helm/README.md b/helm/README.md
index 42d5b3476..4d24099ed 100644
--- a/helm/README.md
+++ b/helm/README.md
@@ -32,6 +32,42 @@ You can override the inference by setting `drivesPerNode` explicitly, e.g.
 (with `--cascade=orphan` to keep pods and PVCs) and recreate it, or perform a
 full reinstall.
 
+## Bring-your-own drives (JBOD)
+
+By default every drive is a PersistentVolumeClaim sized by
+`storageclass.dataStorageSize`. To use disks that you provide yourself, such as
+JBOD `hostPath` or local volumes, set `storageclass.dataStorageSize` to an empty
+string. The chart then renders no data PVCs (no data `volumeClaimTemplates` in
+distributed mode, no data PVC in standalone mode) and no data `volumeMounts`,
+and you supply the drives through `extraVolumes` and `extraVolumeMounts`:
+
+```yaml
+replicaCount: 3
+drivesPerNode: 4
+storageclass:
+  dataStorageSize: ""
+extraVolumes:
+  - name: disk0
+    hostPath: {path: /mnt/disk0, type: Directory}
+  # ... disk1 to disk3
+extraVolumeMounts:
+  - name: disk0
+    mountPath: /data/rustfs0
+  # ... /data/rustfs1 to /data/rustfs3
+```
+
+Mount the drives at `/data/rustfs0` … `/data/rustfs<drivesPerNode-1>` when
+`drivesPerNode` is greater than 1, otherwise at `/data`, so they match the
+generated `RUSTFS_VOLUMES`. The logs PVC is unaffected; set
+`config.rustfs.obs_log_directory` to an empty string to drop it as well. Each
+entry of `pools.list` may override `storageclass.dataStorageSize`
+independently. In standalone mode, `mode.standalone.existingClaim.dataClaim`
+still mounts the named claim as `data`.
+
+Switching `storageclass.dataStorageSize` between empty and non-empty changes
+`volumeClaimTemplates`, so the same StatefulSet recreation rules as for
+`drivesPerNode` apply.
+
 ---
 
 ## Upgrade notes
diff --git a/helm/rustfs/templates/deployment.yaml b/helm/rustfs/templates/deployment.yaml
index 97b663626..22284b5a7 100644
--- a/helm/rustfs/templates/deployment.yaml
+++ b/helm/rustfs/templates/deployment.yaml
@@ -2,6 +2,9 @@
 {{- $tlsEnabled := $tls.enabled | default false -}}
 {{- $logDir := .Values.config.rustfs.obs_log_directory }}
 {{- $logDirEnabled := ne $logDir "" }}
+{{- /* With an empty storageclass.dataStorageSize and no existingClaim.dataClaim,
+       the data volume is supplied through extraVolumes/extraVolumeMounts. */}}
+{{- $dataVolumeEnabled := or .Values.mode.standalone.existingClaim.dataClaim (not (empty .Values.storageclass.dataStorageSize)) }}
 
 {{- if .Values.mode.standalone.enabled }}
 apiVersion: apps/v1
@@ -74,6 +77,7 @@ spec:
       priorityClassName: {{ .Values.priorityClassName }}
       securityContext:
         {{- toYaml .Values.podSecurityContext | nindent 8 }}
+      {{- if or $dataVolumeEnabled $logDirEnabled }}
       initContainers:
         - name: init-step
           image: "{{ .Values.image.initImage.repository }}:{{ .Values.image.initImage.tag }}"
@@ -84,18 +88,23 @@ spec:
             - sh
             - -c
             - |
+              {{- if $dataVolumeEnabled }}
               mkdir -p /data
+              {{- end }}
               {{- if $logDirEnabled }}
               mkdir -p /mnt/rustfs/logs
               chmod 755 /mnt/rustfs/logs
               {{- end }}
           volumeMounts:
+            {{- if $dataVolumeEnabled }}
             - name: data
               mountPath: /data
+            {{- end }}
             {{- if $logDirEnabled }}
             - name: logs
               mountPath: /mnt/rustfs
             {{- end }}
+      {{- end }}
       containers:
         - name: {{ .Chart.Name }}
           image: "{{ .Values.image.rustfs.repository }}:{{ .Values.image.rustfs.tag | default .Chart.AppVersion }}"
@@ -138,8 +147,10 @@ spec:
               mountPath: {{ $logDir }}
               subPath: logs
             {{- end }}
+            {{- if $dataVolumeEnabled }}
             - name: data
               mountPath: /data
+            {{- end }}
       volumes:
       {{- with .Values.extraVolumes }}
       {{- toYaml . | nindent 8 }}
@@ -188,6 +199,7 @@ spec:
             claimName: {{ include "rustfs.fullname" $ }}-logs
             {{- end }}
       {{- end }}
+      {{- if $dataVolumeEnabled }}
         - name: data
           persistentVolumeClaim:
             {{- if .Values.mode.standalone.existingClaim.dataClaim }}
@@ -195,4 +207,5 @@ spec:
             {{- else }}
             claimName: {{ include "rustfs.fullname" $ }}-data
             {{- end }}
+      {{- end }}
 {{- end }}
diff --git a/helm/rustfs/templates/pvc.yaml b/helm/rustfs/templates/pvc.yaml
index d2ddbd95a..ca7f49466 100644
--- a/helm/rustfs/templates/pvc.yaml
+++ b/helm/rustfs/templates/pvc.yaml
@@ -1,4 +1,4 @@
-{{- if and .Values.mode.standalone.enabled (not .Values.mode.standalone.existingClaim.dataClaim) }}
+{{- if and .Values.mode.standalone.enabled (not .Values.mode.standalone.existingClaim.dataClaim) (not (empty .Values.storageclass.dataStorageSize)) }}
 {{- with .Values.storageclass }}
 apiVersion: v1
 kind: PersistentVolumeClaim
diff --git a/helm/rustfs/templates/statefulset.yaml b/helm/rustfs/templates/statefulset.yaml
index 54de97694..ac735009b 100644
--- a/helm/rustfs/templates/statefulset.yaml
+++ b/helm/rustfs/templates/statefulset.yaml
@@ -39,6 +39,10 @@
 {{- $pools := include "rustfs.pools" . | fromJsonArray }}
 {{- range $pool := $pools }}
 {{- $drivesPerNode := int $pool.drives }}
+{{- /* An empty storageclass.dataStorageSize means the data volumes are supplied
+       through extraVolumes/extraVolumeMounts (for example JBOD hostPath disks),
+       so the chart renders no data PVC templates and no data mounts. */}}
+{{- $dataPvcEnabled := not (empty $pool.storageclass.dataStorageSize) }}
 ---
 apiVersion: apps/v1
 kind: StatefulSet
@@ -142,19 +146,23 @@ spec:
       priorityClassName: {{ $.Values.priorityClassName }}
       securityContext:
         {{- toYaml $.Values.podSecurityContext | nindent 8 }}
+      {{- if or $dataPvcEnabled $logDirEnabled }}
       initContainers:
         - name: init-step
           image: "{{ $.Values.image.initImage.repository }}:{{ $.Values.image.initImage.tag }}"
           imagePullPolicy: {{ $.Values.image.initImage.pullPolicy }}
           securityContext:
             {{- toYaml $.Values.containerSecurityContext | nindent 12 }}
+          {{- if $dataPvcEnabled }}
           env:
             - name: DRIVES_PER_NODE
               value: {{ $drivesPerNode | quote }}
+          {{- end }}
           command:
             - sh
             - -c
             - |
+              {{- if $dataPvcEnabled }}
               if [ "$DRIVES_PER_NODE" -gt 1 ]; then
                 for i in $(seq 0 $(($DRIVES_PER_NODE - 1))); do
                   mkdir -p /data/rustfs$i
@@ -162,11 +170,13 @@ spec:
               else
                 mkdir -p /data
               fi
+              {{- end }}
               {{- if $logDirEnabled }}
               mkdir -p /mnt/rustfs/logs
               chmod 755 /mnt/rustfs/logs
               {{- end }}
           volumeMounts:
+            {{- if $dataPvcEnabled }}
             {{- if gt $drivesPerNode 1 }}
             {{- range $i := until $drivesPerNode }}
             - name: data-rustfs-{{ $i }}
@@ -176,10 +186,12 @@ spec:
             - name: data
               mountPath: /data
             {{- end }}
+            {{- end }}
             {{- if $logDirEnabled }}
             - name: logs
               mountPath: /mnt/rustfs
             {{- end }}
+      {{- end }}
       containers:
         - name: {{ $.Chart.Name }}
           image: "{{ $.Values.image.rustfs.repository }}:{{ $.Values.image.rustfs.tag | default $.Chart.AppVersion }}"
@@ -232,6 +244,7 @@ spec:
               mountPath: {{ $logDir }}
               subPath: logs
             {{- end }}
+            {{- if $dataPvcEnabled }}
             {{- if gt $drivesPerNode 1 }}
             {{- range $i := until $drivesPerNode }}
             - name: data-rustfs-{{ $i }}
@@ -241,6 +254,7 @@ spec:
             - name: data
               mountPath: /data
             {{- end }}
+            {{- end }}
       {{- if or $.Values.mtls.enabled $tlsEnabled $.Values.extraVolumes }}
       volumes:
         {{- if or $.Values.mtls.enabled $tlsEnabled }}
@@ -282,6 +296,7 @@ spec:
         {{- toYaml . | nindent 8 }}
         {{- end }}
       {{- end }}
+  {{- if or $logDirEnabled $dataPvcEnabled }}
   volumeClaimTemplates:
     {{- if $logDirEnabled }}
     - apiVersion: v1
@@ -302,6 +317,7 @@ spec:
           requests:
             storage: {{ $pool.storageclass.logStorageSize }}
     {{- end }}
+    {{- if $dataPvcEnabled }}
     {{- if gt $drivesPerNode 1 }}
     {{- range $i := until $drivesPerNode }}
     - apiVersion: v1
@@ -341,5 +357,7 @@ spec:
           requests:
             storage: {{ $pool.storageclass.dataStorageSize }}
     {{- end }}
+    {{- end }}
+  {{- end }}
 {{- end }}
 {{- end }}
diff --git a/helm/rustfs/values.yaml b/helm/rustfs/values.yaml
index b7b622d7e..680d3ef5b 100644
--- a/helm/rustfs/values.yaml
+++ b/helm/rustfs/values.yaml
@@ -8,7 +8,9 @@
 replicaCount: 4
 
 # Number of data drives (PVCs) per pod. Combined with replicaCount this
-# determines the total drive count seen by rustfs.
+# determines the total drive count seen by rustfs. When
+# storageclass.dataStorageSize is empty no PVCs are created and the drives come
+# from extraVolumes/extraVolumeMounts instead.
 # - drivesPerNode > 1: each pod gets N volumes mounted at /data/rustfs0.../data/rustfsN-1
 # - drivesPerNode = 1: each pod gets a single volume mounted at /data
 #
@@ -467,6 +469,22 @@ topologySpreadConstraints:
 
 storageclass:
   name: local-path
+  # Size of each data PVC. Set it to an empty string ("") to stop the chart from
+  # creating data PersistentVolumeClaims: the StatefulSet then renders no data
+  # volumeClaimTemplates (standalone mode renders no data PVC) and no data
+  # volumeMounts, so the drives must come from extraVolumes/extraVolumeMounts,
+  # for example JBOD hostPath or local disks. Mount them at the paths RustFS
+  # expects: /data/rustfs0 ... /data/rustfs<drivesPerNode-1> when drivesPerNode
+  # is greater than 1, otherwise /data. Keep drivesPerNode and replicaCount
+  # accurate because they still drive the generated RUSTFS_VOLUMES. A pool
+  # under pools.list can override this value, including with "". Standalone
+  # mode keeps the data volume when mode.standalone.existingClaim.dataClaim is
+  # set. logStorageSize is independent: the logs PVC is still created unless
+  # config.rustfs.obs_log_directory is empty.
+  # WARNING: switching between an empty and a non-empty value changes the
+  # StatefulSet volumeClaimTemplates, which Kubernetes forbids updating in
+  # place. Delete the StatefulSet with --cascade=orphan and recreate it, or
+  # reinstall.
   dataStorageSize: 256Mi
   logStorageSize: 256Mi
   pvcAnnotations:
diff --git a/scripts/test_helm_templates.sh b/scripts/test_helm_templates.sh
index e6e7907d0..b8d1eeb44 100755
--- a/scripts/test_helm_templates.sh
+++ b/scripts/test_helm_templates.sh
@@ -503,6 +503,102 @@ if grep -q "name: data$" <<<"$generic_eight_by_two"; then
   exit 1
 fi
 
+# Issue #8665: an empty storageclass.dataStorageSize means the drives come from
+# extraVolumes/extraVolumeMounts, so no data PVC templates, no data mounts and
+# no empty `storage:` request may be rendered. The logs PVC is unaffected.
+jbod_extra_volumes='[{"name":"disk0","hostPath":{"path":"/mnt/disk0"}},{"name":"disk1","hostPath":{"path":"/mnt/disk1"}}]'
+jbod_extra_mounts='[{"name":"disk0","mountPath":"/data/rustfs0"},{"name":"disk1","mountPath":"/data/rustfs1"}]'
+jbod_statefulset=$(render_distributed_statefulset \
+  --set replicaCount=3 \
+  --set drivesPerNode=2 \
+  --set storageclass.dataStorageSize= \
+  --set-json "extraVolumes=${jbod_extra_volumes}" \
+  --set-json "extraVolumeMounts=${jbod_extra_mounts}")
+if grep -Eq 'name: data(-rustfs-[0-9]+)?$' <<<"$jbod_statefulset"; then
+  echo "Empty dataStorageSize must not render data PVC templates or data volume mounts" >&2
+  exit 1
+fi
+if grep -Eq 'storage:[[:space:]]*$' <<<"$jbod_statefulset"; then
+  echo "Empty dataStorageSize must not render an empty storage request" >&2
+  exit 1
+fi
+if grep -Eq 'DRIVES_PER_NODE|mkdir -p /data' <<<"$jbod_statefulset"; then
+  echo "Empty dataStorageSize must not initialize data directories in the init container" >&2
+  exit 1
+fi
+if ! grep -Fq 'mountPath: /data/rustfs1' <<<"$jbod_statefulset" || ! grep -Fq 'path: /mnt/disk1' <<<"$jbod_statefulset"; then
+  echo "Empty dataStorageSize must keep user-supplied extraVolumes and extraVolumeMounts" >&2
+  exit 1
+fi
+if ! grep -Eq '^[[:space:]]+name: logs$' <<<"$jbod_statefulset"; then
+  echo "Empty dataStorageSize must not affect the logs PVC" >&2
+  exit 1
+fi
+
+# With neither data nor logs PVCs there is nothing to claim or initialize.
+jbod_no_pvc_statefulset=$(render_distributed_statefulset \
+  --set replicaCount=3 \
+  --set drivesPerNode=2 \
+  --set storageclass.dataStorageSize= \
+  --set config.rustfs.obs_log_directory=)
+for absent_key in volumeClaimTemplates initContainers; do
+  if grep -Fq "${absent_key}:" <<<"$jbod_no_pvc_statefulset"; then
+    echo "StatefulSet without data or logs PVCs must not render ${absent_key}" >&2
+    exit 1
+  fi
+done
+
+# A pool may disable its data PVCs independently of the other pools.
+pools_mixed=$(helm template rustfs "$CHART_DIR" \
+  --namespace rustfs \
+  --set secret.rustfs.access_key=test-access-key \
+  --set secret.rustfs.secret_key=test-secret-key \
+  --set pools.enabled=true \
+  --set-json 'pools.list=[{},{"storageclass":{"dataStorageSize":""}}]')
+if grep -Eq 'storage:[[:space:]]*$' <<<"$pools_mixed"; then
+  echo "A pool with empty dataStorageSize must not render an empty storage request" >&2
+  exit 1
+fi
+statefulset_named() {
+  awk -v metadata_name="$1" '
+    function flush() {
+      if (doc ~ /kind: StatefulSet/ && index(doc, "\n  name: " metadata_name "\n") > 0) printf "%s", doc
+      doc = ""
+    }
+    /^---$/ { flush(); next }
+    { doc = doc "\n" $0 }
+    END { flush() }
+  '
+}
+pool0_statefulset=$(statefulset_named rustfs <<<"$pools_mixed")
+pool1_statefulset=$(statefulset_named rustfs-pool1 <<<"$pools_mixed")
+if ! grep -Eq 'name: data-rustfs-0$' <<<"$pool0_statefulset"; then
+  echo "A pool that keeps dataStorageSize must still render its data PVC templates" >&2
+  exit 1
+fi
+if [[ -z "$pool1_statefulset" ]] || grep -Eq 'name: data(-rustfs-[0-9]+)?$' <<<"$pool1_statefulset"; then
+  echo "A pool with empty dataStorageSize must not render data PVC templates or mounts" >&2
+  exit 1
+fi
+
+# Standalone mode: no data PVC and no data volume unless an existing claim is named.
+standalone_jbod=$(render_chart --set storageclass.dataStorageSize=)
+if grep -Eq 'rustfs-data$|storage:[[:space:]]*$' <<<"$standalone_jbod"; then
+  echo "Standalone mode with empty dataStorageSize must not render a data PVC" >&2
+  exit 1
+fi
+if grep -Eq '^[[:space:]]+- name: data$|mountPath: /data$' <<<"$standalone_jbod"; then
+  echo "Standalone mode with empty dataStorageSize must not mount a data volume" >&2
+  exit 1
+fi
+standalone_jbod_claim=$(render_chart \
+  --set storageclass.dataStorageSize= \
+  --set mode.standalone.existingClaim.dataClaim=existing-data)
+if ! grep -Fq 'claimName: existing-data' <<<"$standalone_jbod_claim"; then
+  echo "Standalone existingClaim.dataClaim must still mount when dataStorageSize is empty" >&2
+  exit 1
+fi
+
 # Issue #5416's exact three-node, one-drive topology must render all three
 # ordinal hosts while each StatefulSet pod receives its own explicit anchor.
 three_by_one_configmap=$(render_distributed_configmap --set replicaCount=3 --set drivesPerNode=1)